Narrowband HST images of M87: Evidence for a disk of ionized gas around a massive black hole

Holland C. Ford, Richard J. Harms, Zlatan I. Tsvetanov, George F. Hartig, Linda L. Dressel, Gerard A. Kriss, Ralph C. Bohlin, Arthur F. Davidsen, Bruce Margon, Ajay K. Kochhar

Research output: Contribution to journalArticle

232 Citations (Scopus)


We present HST WFPC2 narrowband Hα + [N II] images of M87 which show a small disk of ionized gas with apparent spiral structure surrounding the nucleus of M87. The jet projects ∼ 19°.5 from the minor axis of the disk, which suggests that the jet is approximately normal to the disk. In a companion Letter, Harms et al. measure radial velocities at r = ± 0″.25 along a line perpendicular to the jet, showing that one side of the disk is approaching at 500 ± 50 km s-1 and the other side of the disk is receding at 500 ± 50 km s-1. Absorption associated with the disk and the sense of rotation imply that the apparent spiral arms trail the rotation. The observed radial velocities corrected for a 42° inclination of the disk imply rotation at ± 750 km s-1. Analysis of velocity measurements at four positions near the nucleus gives a total mass of ∼2.4 ± 0.7 × 109 M within 18 pc of the nucleus, and a mass-to-light ratio (M/L)I = 170. We conclude that there is a disk of ionized gas feeding a massive black hole in the center of M87.

Original languageEnglish
Pages (from-to)L27-L30
JournalAstrophysical Journal
Issue number1 PART 2
Publication statusPublished - 1 Nov 1994



  • Black hole physics
  • Galaxies: ISM
  • Galaxies: individual (M87, NGC 4486)
  • Galaxies: kinematics and dynamics
  • Galaxies: nuclei

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Ford, H. C., Harms, R. J., Tsvetanov, Z. I., Hartig, G. F., Dressel, L. L., Kriss, G. A., Bohlin, R. C., Davidsen, A. F., Margon, B., & Kochhar, A. K. (1994). Narrowband HST images of M87: Evidence for a disk of ionized gas around a massive black hole. Astrophysical Journal, 435(1 PART 2), L27-L30.